I think all of them are accurate, you can also search each one of them on the internet
In 1 mol of CH3OH, you have 4 H-atoms (because 3 H-atoms
are attached to the C-atom, and one H-atom in the OH group). That means
in 0.500 mol of CH3OH, you have 2 H-atoms since it is halved. And then we have Avogadro's constant: 6.02 * 1023.
The question asks for how many hydrogen atoms there are in 0.500 mol CH3OH. Using the numbers that we have (Avogadro's constant and no. of H-atoms), the answer of the question will be something like:
<span>H-atoms in CH3OH = 2 * 6.02 * </span>1023<span> = ~1.2 * 10</span>24
On the inside of the refrigerator door are NOT required Permanent safety markings
<u>Explanation:</u>
Normally in red color the Permanent safety markings arre done. That are wanted on household refrigerators that accept any refrigerant with an A3 flammability grade such as HCs, on or near any evaporators, any exposed refrigerant tubing, near the machine compartment, and on the exterior of the refrigerator.
Each of these markings shall be in words no short than 6.4 mm (1/4 inch) long. Room residents should remove the place quickly regarding the unexpected release of this refrigerant. "DANGER—Risk of Fire or Explosion. Flammable Refrigerant Used. To Be Repaired Only By Trained Service Personnel. Do Not Puncture Refrigerant Tubing.” is the quote to be marked in the above specified places.